This is a NCSTAR Rail known as the Quad Rail Gen 3, model MAR4S.
NCSTAR's Gen 3 .223/5.56 Carbine Length Quad Rail Handguard is now lighter and has a slimmer profile than earlier models. The solid quad rail provides a steady platform for attaching optics" lasers" bipods and other accessories.
Features:
Black finish
Aluminum alloy Type II anodized;Easy to install;Mounting tool included
